Handling kwargs to be passed to pandas.ExcelFile

Detects kwargs passed to `IamDataFrame.__init__` and to `read_pandas` that
need to be passed to `pandas.ExcelFile.__init__` to be handled properly.

pyam/core.py

@@ -70,6 +70,7 @@
     remove_from_list,
     to_list,
     write_sheet,
+    get_excel_file_with_kwargs,
 )
 from pyam.validation import _exclude_on_fail, _validate
 
@@ -197,7 +198,7 @@ def _init(self, data, meta=None, index=DEFAULT_META_INDEX, **kwargs):  # noqa: C
 
         # if initializing from xlsx, try to load `meta` table from file
         if meta_sheet and isinstance(data, Path) and data.suffix in [".xlsx", ".xls"]:
-            excel_file = pd.ExcelFile(data)
+            excel_file, kwargs = get_excel_file_with_kwargs(data, **kwargs)
             if meta_sheet in excel_file.sheet_names:
                 self.load_meta(excel_file, sheet_name=meta_sheet, ignore_conflict=True)
 

pyam/utils.py

@@ -94,13 +94,30 @@ def write_sheet(writer, name, df, index=False):
         writer.sheets[name].set_column(i, i, width)  # assumes xlsxwriter as engine
 
 
+def get_excel_file_with_kwargs(path, **kwargs):
+    """Return a `pandas.ExcelFile` and a dict of unused kwargs.
+
+    When reading an Excel file, this function finds keyword arguments that
+    should be passed to `pandas.ExcelFile`, and returns a `pandas.ExcelFile`
+    instance along with the remaining keyword arguments (which presumably
+    will be used for other purposes by the calling function).
+    """
+    EXCEL_FILE_KWS = ('engine', 'storage_options', 'engine_kwargs')
+    kwargs = kwargs.copy()
+    excel_file_kwargs = {
+        k: kwargs.pop(k) for k in EXCEL_FILE_KWS if k in kwargs
+    }
+    return pd.ExcelFile(path, **excel_file_kwargs), kwargs
+
+
 def read_pandas(path, sheet_name=["data*", "Data*"], *args, **kwargs):
     """Read a file and return a pandas.DataFrame"""
 
     if isinstance(path, Path) and path.suffix == ".csv":
         return pd.read_csv(path, *args, **kwargs)
 
-    with pd.ExcelFile(path) as xl:
+    xlfile, kwargs = get_excel_file_with_kwargs(path, **kwargs)
+    with xlfile as xl:
         # reading multiple sheets
         sheet_names = pd.Series(xl.sheet_names)
         if len(sheet_names) > 1: